But with goldreaching a 17-year high on the international market, the miners, both large-scale and small, are returning to Johannesburg in scenes reminiscent of the mid-19th century gold rush.

Except that this time around, the popular image of the gold rush - miners panning for nuggets with picks, shovels and axes - bears little resemblance to the sight of the improved infrastructure surrounding today's miners.

Environmentalists, however, still complain that the big operators are leaving devastation in their wake.

Thanks to gold, Johannesburg is a byword for world-class highways, skyscrapers and spacious suburbs. But descending from the M1 motorway into one of the dumps being recycled at Crown Mines, you travel into a different world. It is rugged, with huge mounds of sand and cut-marks contouring round the slopes, generally a moonscape bearing no resemblance to the nearby suburbs. White sand spews out in solution from giant tanks, piling up across a wide expanse. It is only 15km north of Johannesburg.

"Gold digging has always been a scheme to get rich quick," said one worker.

"When the prices are good, you move in and extract as much as you can. We will restore the land and when you come back you might find another suburb like this," he said, gesturing to surrounding houses.

But that is no consolation to environmentalists, such as Catherine Pienaar, who fear that excessive amounts of cyanide used in recycling the gold dumps will have detrimental effects on the health of the surrounding communities, particularly those who have become small-time gold panners.

Ms Pienaar says the illegal small-time panners, who do not have the technology to contain the effects of cyanide poisoning, are at great risk.

The government has tried to stop the local panners from flocking to the dumps. But Ms Pienaar says they should force companies to take more precautions to ensure cyanide solutions are prevented from escaping into the environment, and jeopardising the health of the poor. Cyanide is also harmful to wildlife: many species, especially birds, are susceptible to poisoning.

Another major environmental risk from contaminated solutions is the possibility of slow leaching into the water-table. "That is our greatest fear from the gold rush," Ms Pienaar said.

South Africa is the world's largest gold producer with production averaging about 400,000kg a year. In 2003, production fell by an estimated 6.5 per cent to 373,000kg, marking the lowest level since 1956, but gold still accounted for an estimated 39 per cent of dollar export revenue.

Industry officials say that the biggest hurdle to production is that 95 per cent of South Africa's working gold mines are underground operations, reaching depths of more than 4km. This, coupled with declining quality, has resulted in soaring costs of production.

And it also explains the preference for recycling the old dumps of Johannesburg.